Methods for bone and other tissue preparation

ABSTRACT

Methods are provided for surgical lavage including pumping liquid to bone and other tissue surfaces with a reciprocating pump mechanism operated by pressurized gas wherein pressurized exhaust gas is further utilized to accelerate the pulsed liquid. A first valve arrangement is provided to bypass the pumping mechanism to direct pressurized gas directly onto the tissue surface without the presence of liquid from the device. A second valve arrangement is provided for optionally venting at least a portion of the exhaust gas to the atmosphere instead of directing it to the tissue surface. An additive line delivers additive to the gas bypass line for delivery of the additive to the tissue surface with the flowing gas stream.

FIELD OF THE INVENTION

The invention relates generally to hand-held surgical lavage devices andmethods, and more particularly to hand-held surgical lavage devices andmethods for cleaning of the exposed tissues in surgeries such asprosthetic joint replacement, or repair of traumatic injury. Theinvention also relates generally to hand-held surgical delivery devicesand methods, and more particularly, to surgical lavage/irrigationdevices and methods for delivery of various therapeutic or bioactiveagents to the surfaces and recesses of a surgical site such as boneprepared to receive a prosthetic implant.

BACKGROUND OF THE INVENTION

In the field of surgery, the importance of thorough cleaning of exposedtissues has long been recognized. In orthopedic surgery, the need forcleaning bony tissues is an added concern. Traumatic wounds, which caninvolve both soft and bony tissues, must be thoroughly cleansed ofcontaminants in order to minimize the risk of serious infection. Thesame risk requires that soft and bony tissues at surgical sites forprocedures such as prosthetic joint replacement must also be thoroughlycleansed.

Cemented joint replacement surgery also requires especially thoroughcleaning of the bone bed sculpted to receive an implant, for twoadditional reasons. The bone cement (typically polymethyl methacrylate)which secures the implant to the prepared bone is not an adhesivematerial, and accordingly, successful prosthetic fixation depends uponintimate mechanical interlock between cement and the open,three-dimensional network of cancellous bone surrounding the implantsite. Thorough removal of fat, debris, and fluids from this bony networkprevents these materials from forming an interposed layer between cementand bone, and thus allows for more direct cement-bone contact, helpingto contribute to improved long-term mechanical fixation. Secondly,placement of cement into a prepared bony cavity, followed by insertionof the implant, often generates significant pressures which can forcefat or particulate debris into the patient's circulatory system. Fatembolism has been a serious potential complication of cemented jointreplacement surgery, but the incidence has been shown to be reduced bythorough cleaning, which removes substantial volumes of fat, marrow, anddebris from the prepared bone bed.

Cleaning, or lavage, of the prepared bone surface or other tissue isgenerally accomplished by rinsing and flushing with a saline solution,which washes away surface debris. Traditionally, this has beenaccomplished by manually squirting saline from a bulb-style syringe.More recently, a variety of commercially available lavage devices havebeen developed, which deliver the saline solution in a pulsating stream,at higher flow rates and impact forces than can be readily achieved withmanual delivery. Examples of these pulsatile lavage devices aredescribed in U.S. Pat. No. 4,662,829 (Nehring), U.S. Pat. No. 4,583,531(Mattchen), and U.S. Pat. No. 5,046,486 (Grulke et al.). Each of thesedevices delivers a stream of discrete pulses of saline to the surgicalsite.

Pulsatile lavage has been shown to contribute to improved cleaning ofthe trabecular bone. Intermittent flow may temporarily interrupt theformation of hydrostatic blockages in the bony pores, and further thepulses of saline may help the bone to "throw off" debris, as it reboundsfrom the impact of each delivered pulse. Mattchen and Grulke et al. bothemphasize the importance of sharp irrigant pulses for effectivecleaning. In both of these devices, the pulses of saline are deliveredwith relatively sharp on-off characteristics, so that the liquid streamcomprises a series of repetitive impacts.

Each of the three devices mentioned above (Nehring, Mattchen, Grulke etal.) relies upon a pressurized gas to drive the pumping action. The gastypically employed is compressed nitrogen gas, which is readilyavailable in the operating room because it is a common power source forsurgical instruments such as drills and saws. The Nehring patentdescribes a diaphragm pump, in which the liquid is moved by theexpansion of a flexible elastic diaphragm under pressure from the gas.Expansion of the diaphragm pressurizes the liquid contained in anadjacent chamber. Both the Mattchen and Grulke patents describepiston-style pumps to drive the saline solution. In each, the pump ispowered by a compressed gas, as mentioned above. The Mattchen deviceemploys a sliding valve timing assembly, and utilizes a disposable pumpcartridge which is locked into position in a resterilizable handpiecefor use. The Grulke device utilizes a spring-loaded piston pump,contained within a fully disposable handpiece unit to eliminate the needfor hospital sterilization.

In all three of these devices, care is taken to ensure that the pathwaysfor saline and pressurized gas are kept completely separate, and thatthe gas is safely vented away from the surgical site. This is animportant patient safety feature, because the nitrogen gas typicallyemployed with surgical instruments diffuses very slowly in physiologicalfluids, and therefore blood uptake of the gas can form a gas embolus,possibly leading to significant physiological disruption. Pressurizedair directed at the surgical site could lead to similar problems, bothbecause of its high nitrogen content and because oxygen also diffusesslowly in physiological fluids.

U.S. Pat. No. 5,037,437 (Matsen) describes a device for cleaning anddrying the bone bed with a stream of physiologically benign flowingpressurized gas, to aid in more complete removal of debris and fluids.Flowing gas has been found to be helpful in loosening impacted bonydebris and in lifting debris, fat and fluids from trabecular recessesand bringing them to the surface for more complete removal, which allowsfor better cement-bone interdigitation. This patent teaches the use ofcarbon dioxide or another gas with similar diffusibility inphysiological fluids, an important safety feature to minimize any riskof gas embolism, as noted above.

Surgical procedures for repair of a variety of conditions caused bydisease or traumatic injury may involve the application at the surgicalsite of one or more agents which serve therapeutic purposes. An exampleof this would be the application of antibiotics to the tissues exposedby the surgical or traumatic wound, to minimize the risks of woundinfection and its accompanying physiological complications.

Surgical lavage devices are generally used to irrigate and cleanse thewound with saline solutions, and antibiotics may be added to the liquidsolutions so that they can be washed over the surgical site. Othertherapeutic or bioactive agents are applied topically to the exposedtissues. One example of this would be the use of topical hemostaticagents, often applied to the exposed bone surfaces to reduce bonebleeding in orthopedic joint replacement procedures. An agent such asthrombin or epinephrine is mixed into a small amount of liquid anddabbed onto the bone with surgical gauze sponges. In other instances,materials such as hydroxyapatite compounds are applied to the sculptedbone bed in order to facilitate bone growth and repair.

In contemporary surgical devices, delivery mechanisms for such materialsare limited to admixing with volumes of saline, or manual delivery suchas with sponges. In the first instance, the materials applied arediluted by the liquid solution, and are flushed through and across thesite in the liquid stream, limiting the user's ability to place thematerial at a specific site. In the second instance, delivery efficiencyis limited to the uppermost exposed surfaces which can be contacted by asponge or similar device.

There is a need in the art for surgical devices and methods whichaddress at least some of the above concerns or other concerns forpreparing bone and other tissues.

SUMMARY OF THE INVENTION

The present invention enhances the efficiency of pulsatile saline orother liquid lavage by increasing the impact force which each salinepulse delivers. Increased saline impact force and momentum help todislodge impacted debris, marrow and fat from the bone bed. Thisenhancement of saline lavage is accomplished by combining pulsed salineflow with pulses of a physiologically benign pressurized gas, such ascarbon dioxide, in a hand-held lavage device. The device offersincreased impact and cleaning efficiency via the rapidly alternatingflow of saline and gas. The same pressurized gas is used as a powersource for the saline pump mechanism. The gas utilized to drive eachstroke of the pump mechanism is not vented away from the site, but isinstead recirculated to the downstream end of the device, just upstreamof the delivery nozzle. Each pulse of saline delivered by the pumpmechanism is therefore immediately followed by a pulse of pressurizedgas, which serves to further accelerate the saline pulse outward throughthe delivery nozzle. Thus, the resulting lavage stream does not merelyinclude repetitive pulses of saline, but instead includes alternatepulses of saline and pressurized gas. The saline impact force issignificantly increased (as much as 100%) over that delivered by thesaline pumping mechanism alone. The alternate gas pulses also aid inloosening debris and preventing pooling of liquid in the trabecularrecesses. The present invention also provides a gas bypass line tobypass the pump mechanism for gas-only delivery. The present inventionalso provides for liquid-only delivery, where the gas is vented to theatmosphere.

In one preferred embodiment, a surgical handpiece for effecting lavageis configured to accept a sterile disposable pump portion, and furtherincorporates a valve arrangement enabling the user to switch between theenhanced saline/gas combination lavage and straight gas lavage, so thatfinal cleaning and drying of the implant site can be accomplished withflowing gas alone. Such an embodiment might also include a further valvesetting, to allow the user to select a low-impact saline-only lavage,for use on soft tissues and other areas where irrigation is a moresignificant need than debridement and cleaning. Adjustment of this valvesetting could allow for variability in lavage impact force, by varyingthe amount of gas which is vented and/or recirculated. In the preferredembodiment, a gas such as carbon dioxide, with a high diffusioncoefficient in physiological fluids, would be employed.

The present invention is useable in a variety of surgical proceduresincluding bone preparation for prosthetic implant, and cleansing anddebridement of tissues comprised by trauma.

The present invention also delivers any of a variety of therapeutic orbioactive agents to a specific surgical site with a flowing gas stream.Preferably, the agents are delivered by utilizing the flowingpressurized gas stream used for final bony lavage as a delivery carrier.User convenience is enhanced by adding this delivery means to ahand-held surgical lavage device which delivers liquid and gas lavagefrom a single handpiece.

In one preferred embodiment, a surgical handpiece for effecting lavageincorporates a valve arrangement enabling the user to switch betweenliquid lavage and gas lavage. The gas lavage setting accommodates theaddition of a reservoir of the desired additive agent which provides forintroduction and dispersion of the agent into the flowing gas stream atthe user's discretion. The handpiece of this embodiment allows the userto perform all surgical irrigation/lavage/delivery functions with asingle self-contained unit. The present invention therefore is usable ina wide variety of surgical procedures, including most especiallyorthopedic procedures involving the preparation of bony tissues forrepair or receipt of orthopedic devices such as prosthetic jointreplacements.

BRIEF DESCRIPTION OF THE DRAWINGS

Throughout the following views, reference numerals will be used on thedrawings, and the same reference numerals will be used throughout theseveral views and in the description to indicate same or like parts ofthe invention:

FIG. 1 is a schematic diagram of a lavage device in accordance with theinvention.

FIG. 2 is a cross-sectional view of one preferred embodiment of a lavagedevice in accordance with the present invention.

FIG. 3 is an enlarged cross-sectional view of the pump portion of thelavage device of FIG. 2 showing the device in the gas-only mode ofoperation.

FIG. 4 shows the pump portion in the soft pulsing (liquid-only) mode ofoperation.

FIG. 5 shows the pump portion in the accelerated pulsing (gas andliquid) mode of operation during the filling phase.

FIG. 6 shows the pump portion in the accelerated pulsing mode ofoperation during the pulse delivery phase.

FIG. 7 shows the pump portion in the accelerated pulsing mode ofoperation at the end of the pulse delivery phase.

FIG. 8 is an enlarged cross-sectional view of the second plunger portionof the plunger arrangement of the pump mechanism.

FIG. 9 is an end view of the second plunger portion of the plungerarrangement of the pump mechanism.

FIG. 10 shows the pump portion in a further enlarged view in an interimsetting in which a portion of the exhaust gas is vented, and a portionis redirected to the bone/other tissue surface.

FIG. 11 is a schematic diagram of a lavage device like that shown inFIG. 1, and including a reservoir of a desired additive agent.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides for devices and methods for preparingbone/other tissue surfaces for prosthetic implantation and othersurgical procedures by the application of liquid and/or gas. Preferably,the liquid is saline or other cleansing or therapeutic liquid pumped inshort bursts to a bone/other tissue surface during surgery. Preferably,the gas is carbon dioxide (CO₂), or other physiologically benignpressurized gas. The liquid is preferably directed at the bone/othertissue surface in bursts of short duration. The gas is utilized to drivethe pump mechanism, wherein the exhaust gas is either vented to theatmosphere or redirected at the bone/other tissue surface in combinationwith the liquid for increased surface cleansing or treatment of thebone/other tissue. Interim settings, in which a portion of the exhaustgas is vented while the remainder is redirected to the bone/tissuesurface, are also possible in this embodiment. Alternatively, the gasbypasses the pump mechanism and is directed onto the bone/other tissuesurface for further cleaning and localized drying of the bone bed. Anadditive agent reservoir may be added to the gas bypass line.

Referring now to FIG. 1, a schematic of a lavage device 10 is shown inaccordance with the invention. A gas inlet line 12, and a liquid inletline 14 provide inlet passages for the gas and the liquid, respectively,for use with lavage device 10. Gas source 16, preferably carbon dioxide,is supplied to gas inlet line 12 at a pressure above atmosphericpressure, such as 50 or 75 psi for example. Liquid source 18, preferablysaline or other liquid, is supplied to liquid inlet line 14.

In the preferred embodiment, an inlet valve, or first valve 20, isinterconnected to gas inlet line 12. A pump gas inlet line 22 connectsfirst valve 20 to a gas driven reciprocating pump mechanism 30. It is tobe appreciated that first valve 20 is optional in that gas inlet line 12could be connected directly from gas source 16 to pump mechanism 30.First valve 20 could be either a linear or rotary style valve. In thepreferred embodiment including first valve 20, a gas bypass line 24 runsfrom first valve 20 and bypasses pump mechanism 30 and connects to anozzle 32 directly. As shown by FIG. 1, gas source 16 throughappropriate control of first valve 20 is utilized to either operate pumpmechanism 30 or to be applied directly to the bone surface at nozzle 32in a controllable stream.

Pump mechanism 30 is a reciprocally driven pump mechanism, such as adiaphragm pump, or a piston pump, driven by pressurized gas. Pumpmechanism 30 pumps liquid supplied from liquid source 18 through liquidinlet line 14 and a suitable check valve 15 to a liquid outlet line 34connecting pump mechanism 30 to nozzle 32 through a suitable check valve33. Check valves 15 and 33 maintain proper directional control of theliquid being pumped and prevent possible contaminating backflow.

Exhaust gas from pump mechanism 30 exhausts from pump mechanism 30 at apump gas outlet line 36. An outlet valve, or second valve 38, directsexhaust gas from pump gas outlet line 36 to either an exhaust port 40 ora gas return line 42 from second valve 38 to nozzle 32. An interimsetting is also possible, which directs gas to both portssimultaneously. When second valve 38 directs exhaust gas to gas returnline 42, enhanced delivery of liquid from nozzle 32 is provided. Becauseof the reciprocating action of pump mechanism 30, the exhaust gas isreleased into gas outlet line 36 at the completion of the liquid pumpingstroke which drives the liquid pulse into delivery nozzle 32. The gaspulse enters delivery nozzle 32 immediately behind the liquid pulse andimparts additional momentum to it. Alternating pulses of liquid and gasare thereby delivered through nozzle outlet 44 to the bone/other tissuesurface. Second valve 38 could be either a linear or rotary style valve.

If enhanced output of the liquid from nozzle 32 is not desired, secondvalve 38 is operated to direct exhaust gas to exhaust port 40 instead ofto gas return line 42. It is to be appreciated that second valve 38 isoptional in that pump gas outlet line 36 could be connected directlyfrom pump mechanism 30 to nozzle 32. However, as shown by the preferredembodiment of FIG. 1, gas source 16 is utilized to operate pumpmechanism 30 and then, through appropriate control of second valve 38,either vented to the atmosphere or directed, fully or in part, to theinlet end of nozzle 32 to enhance delivery of the liquid pulses.

Preferred lavage device 10 is therefore operable in several modes. Afirst general mode of operation involves pumping liquid onto thebone/other tissue surface through nozzle 32 by pump mechanism 30. Withinthis mode of operation, at least two variations are possible. A firstvariation includes accelerated pulsing of the liquid by operating valve38 to direct exhaust gas into gas return line 42 to nozzle 32. Suchmanner of operation (gas and liquid) is useful in initialcleaning/treating of the bone surface or other tissue.

A second variation of operation is a soft pulsing (liquid-only) modewhere second valve 38 directs exhaust gas to exhaust port 40 instead ofto nozzle 32. The liquid exits nozzle 32 under the influence of pumpmechanism 30 only. Such manner of operation is useful incleaning/treating or conventional bathing/irrigation of softer tissue.

A third optional variation of operation is a partially acceleratedpulsing mode, in which a portion of the exhaust gas is vented, while theremainder is directed into gas return line 42 to nozzle 32. This interimsetting may be particularly useful for cleaning traumatic wounds or bonestock which is weakened by disease processes. The relative amounts ofgas vented to the atmosphere and delivered to the nozzle could be varieddepending on the positioning of valve 38, if valve 38 is a variableposition valve between the full accelerated pulsing of the liquid andgas, and the soft pulsing of liquid only settings.

A second general mode of operation involves operating first valve 20 tobypass pump mechanism 30 and direct gas through gas bypass line 24directly to nozzle 32 for application to the bone surface or tissue.Such mode of operation is useful in a final step for cleaning and dryingbone surfaces and/or removing loose debris.

Optionally, check valves may be provided in gas inlet line 12, pump gasinlet line 22, gas bypass line 24, pump gas outlet line 36, and gasreturn line 42 to maintain proper directional control of the gas flow.

In testing of the flow characteristics of the enhanced liquid flow vs.liquid only flow, it has been found that the impact force developed inthe enhanced liquid flow of the full accelerated pulsing mode is twiceas great as the liquid only flow of the soft pulsing mode.

One potential benefit of this enhanced saline lavage system is that moreefficient cleaning can save operative time. If debris is removed morequickly and efficiently, cleaning can be accomplished with a lesservolume of liquid, and less liquid used also equates to less time neededfor drying. Reduced volumes of liquid can also potentially reduce themagnitude of risk of cross-contamination of operating room personnelexposed to blood-borne pathogens when irrigating liquid and debris aresplashed from the surgical site.

An additional benefit to this design as described here is the obviationof an additional power source for separately lavaging and drying thebone bed. Currently, the saline is pumped using either air ornitrogen-powered pumps, as described above in the prior art, or usingelectrical pumps. A separate source of carbon dioxide is then requiredfor a final cleaning and drying technique with pressurized gas as inMatsen, for example. In the present invention, the carbon dioxide sourceprovides both power for the liquid pump and pressurized gas for cleaningpurposes. In the preferred embodiment, both saline and pressurized gascan be provided through a single combination handpiece, or handleportion, and nozzle assembly, or pump portion, with removable nozzle.The pump portion may be provided as a presterilized component; theseparate handle portion and interchangeable nozzles can be disposable orresterilizable.

Referring now to FIGS. 2-10, one preferred embodiment of a lavage device110 is shown. Lavage device 110 includes a pump portion 112, and ahandle portion 114 which is separable from pump portion 112 at a latch134. Such construction permits disposability of pump portion 112 andreuse of handle portion 114.

A gas source 116 interconnects via a conduit 120 to lavage device 110 atan inlet 122. A first gas line 124 and a second gas line 126 link inlet122 to pump portion 112. A trigger arrangement 128 provides operatorcontrol of the gas flow from gas source 116 to pump portion 112.

A liquid line 130 links liquid source 118 to pump portion 112 of lavagedevice 110. A check valve 132 provides appropriate directional flowcontrol over liquid entering pump portion 112.

The gas enters pump portion 112 at a first passage 136. A valve 140 isoperatively positioned to direct gas flow from first passage 136 to oneor more of three locations in the preferred embodiment. In a first modeof operation as shown in FIG. 3, gas flow is directed from first passage136 to a gas bypass line 152 which leads to a nozzle 154 to exit lavagedevice 110 at a nozzle opening 156. Nozzle 154 is one example of anozzle structure mounted to pump portion 112 with a latch arrangement158. Other nozzles are possible depending on the desired flowcharacteristics, direction of flow, and location of a nozzle outlet 156desired by the operator.

Valve 140 includes a stem 142 positioned in chamber 148. A plurality ofperipheral seals 144, 145, 146, 147 are provided on stem 142 to sealagainst various portions of chamber 148. Stem 142 includes a recessedregion 150 which interconnects first passage 136 to gas bypass line 152in the gas-only mode of operation shown in FIG. 3.

Referring now to FIG. 4, valve 140 is shown in a second mode ofoperation, the liquid-only soft pulsing mode. Valve 140 directs gas flowfrom first passage 136 to a pump inlet passage 160 for operation of aplunger arrangement 170 to pump liquid. The gas exhausts through a pumpexhaust passage 161 through an interior passage 162 of stem 142 of valve140 to a side outlet 164 which permits the gas to be exhausted from pumpportion 112 at an exhaust port 166 to the atmosphere. The direction ofexhaust port 166 can be varied so as to not exhaust onto the patient orthe operator. Tubing can also be attached to this port to direct theexhaust gas away from the operative field. The gas entering pump inletpassage 160 provides reciprocating motion of plunger arrangement 170 topump liquid from a liquid inlet 176 to a chamber 178 to a pump outlet172. A check valve 174 provides directional flow control of the liquidfrom plunger arrangement 170.

Referring now to FIG. 5, valve 140 is in a third mode of operation, theaccelerated pulsing mode. Gas from first passage 136 is directed to pumpinlet passage 160 to operate plunger arrangement 170. Exhaust gas exitsat pump exhaust passage 161 entering interior passage 162 and exiting ata side passage 168 to gas line 152 which directs the gas behind thepumped liquid at nozzle 154 to provide the accelerated pulsed liquid.

Valve 140 can be two separate valves if desired. In that case, eachvalve would need at least two positions. One valve would control gasinlet flow, and the other would control gas outlet flow.

Referring now to FIG. 5-9, operation of the plunger arrangement 170 willbe described in greater detail. With respect to FIGS. 5-7, valve 140 isshown in the accelerated pulse mode of operation. Plunger arrangement170 operates in a similar manner in both the accelerated pulsing mode ofoperation shown in FIGS. 5-7, and the soft pulsing mode of FIG. 4. Asshown in FIG. 5, plunger arrangement 170 includes a large spring 180which biases a first plunger portion 182 to a spaced apart distance fromcheck valve 174. A large seal 185 seals the liquid from the gas. Asecond plunger portion 186 is mounted to first plunger portion 182 forreciprocating movement. A small spring 184 biases second plunger portion186 to the position shown in FIGS. 5 and 7 relative to first plungerportion 182.

Peripheral holes 190 in a disc 188 of second plunger portion 186 areprovided to allow gas entering at pump inlet passage 160 to push firstplunger portion 182 against spring 180 toward check valve 174 to pumpliquid in chamber 178. As first plunger portion 182 moves toward checkvalve 174, the gas will act to separate first plunger portion 182 fromsecond plunger portion 186 against the spring force supplied by smallspring 184 as shown in FIG. 6. Mechanical contact occurring between theinternal shoulder 183 of first plunger portion 182 and the flangedportion 187 of second plunger portion 186 will begin to draw disc 188away from exhaust passage 161, as shown in FIG. 6. As the gas begins toexhaust, small spring 184 rapidly draws second plunger portion 186toward first plunger portion 182 as shown in FIG. 7. Pump exhaustpassage 161 is large relative to pump inlet passage 160, allowing thegas to exhaust quickly at the end of each cycle.

As shown in FIGS. 8 and 9, disc 188 of second plunger portion 186includes a central gas stopper portion 192. Central gas stopper portion192, when pulled away from pump exhaust passage 161, allows the gas torapidly exhaust from the pumping chamber 178, which in turn allows largespring 180 to move first plunger portion 182 and second plunger portion186 as a unit back to the position of FIG. 5 to close pump exhaustpassage 161. Return of the plungers to their original position drawsliquid into chamber 178 for the next pulse. In this manner, the pulsesof liquid are pumped by plunger arrangement 170.

Referring now to FIG. 10, valve 140 is shown in an interim settingbetween the soft liquid-only pulsing mode and the accelerated pulsingmode. In the interim setting, exhaust gas enters interior passage 162. Aportion of the exhaust gas exits at side passage 168 to gas line 152which directs the gas behind the pumped liquid at nozzle 154 to providea partially accelerated pulsed liquid. The remaining portion of theexhaust gas passes from interior passage 162 to side outlet 164 whichpermits the gas to be exhausted at exhaust port 166 to the atmosphere.The relative amounts of exhaust gas exiting at exhaust port 166 orentering gas line 152, respectively, can be varied in the preferredembodiment, depending on the position of valve 140.

The present invention also provides for devices and methods for surgicaldelivery of various therapeutic or bioactive additive agents separatelyfrom or in conjunction with surgical lavage and irrigation for cleansingand preparation of bony sites or surrounding soft tissues, in surgicaland traumatic wounds. Preferably, the irrigating liquid is salinesolution or other liquid cleansing agent, pumped in a pulsatile streamto bone/other tissue surface during surgery. Preferably, lavage isperformed with this liquid in conjunction with carbon dioxide (CO₂), orother physiologically benign pressurized gas. The gas is utilized todrive the pump mechanism, and is further utilized to control variousmodes of liquid delivery. Alternatively, the gas bypasses the pumpmechanism and is directed onto the bone/other tissue surface for furthercleaning and localized drying of the prepared bone bed. In a furtherutilization, the flowing dry gas stream is utilized as a carrier tofacilitate localized delivery of a variety of additive agents.

Referring now to FIG. 11, a schematic of a lavage device 210 is shown inaccordance with the invention. Lavage device 210 is similar to lavagedevice 10 shown in FIG. 1. A gas inlet line 12, a liquid inlet line 14,and an additive inlet line 226 provide inlet passages for the gas,liquid, and additive agents, respectively, for use with lavage device210. Gas source 16, preferably carbon dioxide, is supplied to gas inletline 12 at a pressure above atmospheric pressure, such as 50 or 75 psi,for example. Liquid source 18, preferably saline or other liquid, issupplied to liquid inlet line 14. Additive source 228, in a powder orsuspension form, is optionally supplied to additive inlet line 226.

Lavage device 210 is useable in a similar manner as lavage device 10with respect to the mode of operation allowing delivery of liquid. Inthe second general mode of operation, first valve 20 is operated tobypass pump mechanism 30 and direct gas through gas bypass line 24directly to nozzle 32 for application to the bone surface or tissue.Within this mode of operation, two variations are possible. An inletport 225 for inlet of additive source 228 through additive inlet line226 permits uptake of the additive agent by the flowing gas stream, anddirects gas and additive together to nozzle 32 for delivery to the boneor tissue surface. This mode can be used whenever the operator desiresdelivery of the specific additive agent selected. Alternatively,additive inlet port 225 can be sealed so that the gas in gas bypass line24 passes directly to nozzle 32. This mode of operation is useful as afinal step for cleaning and drying the bone surface and/or removingloose debris. Optionally, a check valve may be provided in additiveinlet line 226 to maintain proper directional flow control.

In the process of preparing a bone bed or other surgical site, device210 would be utilized after the debris and fluids had been flushed awayby liquid lavage and preliminary gas lavage. The additive agent could bedelivered as a dry particulate in the flowing gas stream, or could bemixed in a small amount of liquid prior to surgical delivery. Thisliquid mixture could then be atomized and delivered as a fine mist orspray in conjunction with the flowing dry gas stream.

This delivery method could be utilized for placement of a therapeutic orbioactive material which the operator did not want diluted or flushedaway by liquid delivery. Flowing gas travels through all the openinterconnected recesses of the bony network surrounding the surgicalsite and can therefore ensure contact of the desired material withspecific locations, deep and superficial. Materials which could bedelivered in this fashion include antibiotics and similar antisepticagents; hydroxyapatite or similar bioactive materials intended topromote bone healing and re-growth; topical and resorbable hemostaticagents, such as thrombin, epinephrine, adrenaline, microcrystallinecollagen, gelatins, or oxidized cellulose, intended to control oozingblood from the bone, which can otherwise interfere with the cement-boneinterface; and other chemical agents serving a purpose in healing orfixation, such as, for example, "primers" for future bone cementmaterials.

From the foregoing detailed description of the present invention, it hasbeen shown how the objects of the invention have been obtained in apreferred manner. However, modifications and equivalents of thedisclosed concepts, such as those which would readily occur to oneskilled in the art, are intended to be included within the scope of theclaims.

What is claimed is:
 1. A method of preparing bone and other tissuecomprising the steps of:a) supplying pressurized gas to a pump devicehaving a gas-driven pump mechanism for pumping liquid and a nozzleinterconnected to the pump mechanism; b) supplying liquid to be pumpedto the pump device; c) reciprocally driving the pump mechanism of thepump device with the gas to pump the liquid to the nozzle of the pumpdevice; d) directing exhaust gas from the pumping mechanism to thenozzle; and e) directing the nozzle at a tissue surface, wherein theliquid and the exhaust gas exit the nozzle.
 2. The method of claim 1,after step e), further comprising the steps of:a) bypassing the pumpmechanism with the gas; b) directing the gas to the nozzle; and c)directing the nozzle at the tissue surface, wherein only the gas exitsthe nozzle.
 3. The method of claim 2, further comprising the step ofadding an additive to the gas bypassing the pump mechanism wherein thegas and the additive exit the nozzle.
 4. The method of claim 1, afterstep e), further comprising the steps of:a) directing the exhaust gasfrom the pump mechanism away from the nozzle and into the atmosphere;and b) directing the nozzle at the tissue surface, wherein only theliquid exits the nozzle.
 5. The method of claim 4, after step b) ofclaim 4, further comprising the steps of:a) bypassing the pump mechanismwith the gas; b) directing the gas to the nozzle; and c) directing thenozzle at the tissue surface, wherein only the gas exits the nozzle. 6.The method of claim 1, after step e), further comprising the steps of:a)directing a portion of the exhaust gas from the pump mechanism away fromthe nozzle and into the atmosphere; and b) directing the nozzle at thetissue surface, wherein the liquid and the remaining portion of the gasexit the nozzle.